Wah-
I mean, seriously folks.
If this is hentai, then what the fuck is goblin slayer? There's is a LOT more nudity on that shit on it's first chapter, it's much more gratuitious, and it has a lot more angles, and it has even less plot on it's first chapter than this one has in it.
Old lady fondled the ladies genitals? Did the same thing to the boys too. It's clearly part of their sick rituals.
The rape scene is two pages, and out of the 10 frames on those 2 pages, 3 of them involved the girls.
Yes, there is a shock factor here, it's very clearly intentional, and sure, I'll say that their reaction is not really appropriate, but the scene feels much more squick rather than not.
Overall, as far as mangas including those kind of scenes go, this one is relatively mature (which I guess tells you more about how shitty other mangas deal with them cough cough goblin slayer cough cough), but sure as hell is far from being a hentai.